huffman.cpp

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/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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 */

// Based on eos' Huffman code

#include "common/huffman.h"
#include "common/util.h"
#include "common/textconsole.h"
#include "common/bitstream.h"

namespace Common {

Huffman::Symbol::Symbol(uint32 c, uint32 s) : code(c), symbol(s) {
}


Huffman::Huffman(uint8 maxLength, uint32 codeCount, const uint32 *codes, const uint8 *lengths, const uint32 *symbols) {
    assert(codeCount > 0);

    assert(codes);
    assert(lengths);

    if (maxLength == 0)
        for (uint32 i = 0; i < codeCount; i++)
            maxLength = MAX(maxLength, lengths[i]);

    assert(maxLength <= 32);

    _codes.resize(maxLength);
    _symbols.resize(codeCount);

    for (uint32 i = 0; i < codeCount; i++) {
        // The symbol. If none were specified, just assume it's identical to the code index
        uint32 symbol = symbols ? symbols[i] : i;

        // Put the code and symbol into the correct list
        _codes[lengths[i] - 1].push_back(Symbol(codes[i], symbol));

        // And put the pointer to the symbol/code struct into the symbol list.
        _symbols[i] = &_codes[lengths[i] - 1].back();
    }
}

Huffman::~Huffman() {
}

void Huffman::setSymbols(const uint32 *symbols) {
    for (uint32 i = 0; i < _symbols.size(); i++)
        _symbols[i]->symbol = symbols ? *symbols++ : i;
}

} // End of namespace Common